Research Article
M.A. Mousavi Shalmani; A. Lakzian; A. Khorasani; V. Feiziasl; A. Mahmoudi; A. Borzuee; N. Pourmohammad
Abstract
In order to assessment of water quality and characterize seasonal variation in 18O and 2H in relation with different chemical and physiographical parameters and modelling of effective parameters, an study was conducted during 2010 to 2011 in 30 different ponds in the north of Iran. Samples were collected ...
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In order to assessment of water quality and characterize seasonal variation in 18O and 2H in relation with different chemical and physiographical parameters and modelling of effective parameters, an study was conducted during 2010 to 2011 in 30 different ponds in the north of Iran. Samples were collected at three different seasons and analysed for chemical and isotopic components. Data shows that highest amounts of δ18O and δ2H were recorded in the summer (-1.15‰ and -12.11‰) and the lowest amounts were seen in the winter (-7.50‰ and -47.32‰) respectively. Data also reveals that there is significant increase in d-excess during spring and summer in ponds 20, 21, 22, 24, 25 and 26. We can conclude that residual surface runoff (from upper lands) is an important source of water to transfer soluble salts in to these ponds. In this respect, high retention time may be the main reason for movements of light isotopes in to the ponds. This has led d-excess of pond 12 even greater in summer than winter. This could be an acceptable reason for ponds 25 and 26 (Siyahkal county) with highest amount of d-excess and lowest amounts of δ18O and δ2H. It seems light water pumped from groundwater wells with minor source of salt (originated from sea deep percolation) in to the ponds, could may be another reason for significant decrease in the heavy isotopes of water (18O and 2H) for ponds 2, 12, 14 and 25 from spring to summer. Overall conclusion of multiple linear regression test indicate that firstly from 30 variables (under investigation) only a few cases can be used for identifying of changes in 18O and 2H by applications. Secondly, among the variables (studied), phytoplankton content was a common factor for interpretation of 18O and 2H during spring and summer, and also total period (during a year). Thirdly, the use of water in the spring was recommended for sampling, for 18O and 2H interpretation compared with other seasons. This is because of function can be explained more by variables and there are more variables compare with other two seasons. Fourthly, potassium concentration in spring and total volume of water in summer would be most appropriate variables for interpretation of data during these seasons
Research Article
B. Ashraf; A. Alizadeh; M. Mousavi Baygi; M. Bannayan Awal
Abstract
Scince climatic models are the basic tools to study climate change and because of the multiplicity of these models, selecting the most appropriate model for the studying location is very considerable. In this research the temperature and precipitation simulated data by BCM2, CGCM3, CNRMCM3, MRICGCM2.3 ...
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Scince climatic models are the basic tools to study climate change and because of the multiplicity of these models, selecting the most appropriate model for the studying location is very considerable. In this research the temperature and precipitation simulated data by BCM2, CGCM3, CNRMCM3, MRICGCM2.3 and MIROC3 models are downscaled with proportional method according A1B, A2 and B1 emission scenarios for Torbat-heydariye, Sabzevar and Mashhad initially. Then using coefficient of determination (R2), index of agreement (D) and mean-square deviations (MSD), models were verified individually and as ensemble performance. The results showed that, based on individual performance and three emission scenarios, MRICGCM2.3 model in Torbat-heydariye and Mashhad and MIROC3.2 model in Sabzevar had the best performance in simulation of temperature and MIROC3.2, MRICGCM2.3 and CNRMCM3 models have provided the most accurate predictions for precipitation in Torbat-heydariye, Sabzevar and Mashahad respectively. Also simulated temperature by all models in Torbat-heydariye and Sabzevar base on B1 scenario and, in Mashhad based on A2 scenario had the lowest uncertainty. The most accuracy in modeling of precipitation was resulted based on A2 scenario in Torbat-heydariye and, B1 scenario in Sabzevar and Mashhad. Investigation of calculated statistics driven from ensemble performance of 5 selected models caused notable reduction of simulation error and thus increase the accuracy of predictions based on all emission scenarios generally. In this case, the best fitting of simulated and observed temperature data were achieved based on B1 scenario in Torbat-heydariye and Sabzevar and, A2 scenario in Mashhad. And the best fitting simulated and observed precipitation data were obtained based on A2 scenario in Torbat-heydariye and, B1 scenario in Sabzevar and Mashhad. According to the results of this research, before any climate change research it is necessary to select the optimum GCM model for the studying region to simulate climatic parameters.
Research Article
B. Mohammadnezhad; J. Behmanesh
Abstract
Bridges are the most important structures in river engineering. One of the most causes in bridges destruction is local scouring around the bridge piers. Many bridges failed in the world because of the extreme scour around piers, which have caused to disappear a lot of investments. Then, it is essential ...
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Bridges are the most important structures in river engineering. One of the most causes in bridges destruction is local scouring around the bridge piers. Many bridges failed in the world because of the extreme scour around piers, which have caused to disappear a lot of investments. Then, it is essential to predict the scour depth around bridge piers. In this research, the Fluent three-dimensional numerical model was used to investigate the scouring around the group cylindrical pier in clear water and uniform sand bed conditions. In this model, sedimentary flow was considered as two-phase flow (water - sand) and Eulerian two-phase model was used. To estimate the parameters of flow turbulence in the water phase, the RNG K-ε model was used. To evaluate and verify the numerical model, the computational results were compared with experimental data. The maximum scour depth in front of the first pier on a numerical model equal to 12.5 cm and in experimental model equal to 12 cm have been measured. Also scour depth at the second pier less than that at the first pier and scour depth at the third pier has been less than the values of the first and second pier .The results showed that the two phase model can simulate the scour phenomena around the pier.
Research Article
M. Ghaemi; A. Astaraei; M. Nassiri Mahalati; S.H. Sanaeinejad; H. Emami
Abstract
Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to ...
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Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to identify intercorrelations among soil properties (chemical, physical and biological) using principal component analysis (PCA) and their relationships with maize yield variability in field. Site variables (18) and maize yield were measured in selected parts of Astan Quds agricultural fields in Mashhad city. The principal component analysis was used to reduce the site variables numbers and remove multicollinearity among variables. The first four PCs with eigenvalues>1 accounted for > 67% of variability in measured soil properties. Soil properties were grouped in four PCs as: (PC1) Soil highly descriptive fertility potential, (PC2) Soil moderately descriptive fertility potential, (PC3) Soil permeability potential, (PC4) Soil aggregation potential. The results showed that the factor of soil highly descriptive fertility potential explained 43% of variance and accounted for 77% of the yield variability in the field. Principal component analysis allows explaining a major part of crop yield variability by removing the multicollinearity.
Research Article
Ashkan Alebouyeh; Saeed Reza Khodshenas
Abstract
Flash flood is due to rapid precipitation in arid and semi-arid areas. This flood is example of unsteady flow which has hydrograph with little time duration and high discharge. Investigation behavior of these floods is very important on sediment transport and characteristics streams. In this research ...
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Flash flood is due to rapid precipitation in arid and semi-arid areas. This flood is example of unsteady flow which has hydrograph with little time duration and high discharge. Investigation behavior of these floods is very important on sediment transport and characteristics streams. In this research evaluated the effect of flash floods on bed load transported to downstream. The input hydrographs are symmetric and Asymmetric triangles. Time duration of hydrograph was selected 90 second and constant and the maximum discharge were changed 6.58 to 16.18 l/s. The median size of particles is 2.5 mm; three bed slopes 0.005, 0.01 and 0.02 were select in these experiments. The results show that a temporal lag was found between the flow hydrographs peak and the sediment hydrograph peak. The temporal lag was found to be about equal to 5 - 11% of flow hydrograph duration. Also bed slope and maximum discharge of hydrograph are effect on upstream erosion and transportation of sediment to downstream. Since increases the bed slope from 0.005 to 0.01 increased 50% bed load transported and with two times the slope it show increase 400% in bed load transported. Bed load transported to downstream with symmetric triangle hydrographs more than symmetric triangle hydrograph.
Research Article
Hamid Mirhashemi
Abstract
In this study, in order to analyze the changes trend of the crop water requirement as the aspect of climate change in East Azerbaijan, we have adopted FAO Penman- Monteith reference crop evapotranspiration and 15 variables associated with it. By using nonparametric methods of Spearman, Man- Kendall ...
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In this study, in order to analyze the changes trend of the crop water requirement as the aspect of climate change in East Azerbaijan, we have adopted FAO Penman- Monteith reference crop evapotranspiration and 15 variables associated with it. By using nonparametric methods of Spearman, Man- Kendall and Sen’s Estimator in twelve monthly and annual series for each station, the trends have been explored. The results of these two test statistics indicate that the significance of the respective phenomenon is being studied in two separate clusters. The first cluster consists of Tabriz and Maragheh stations the entire time series, the time series exceptions of April in Tabriz, the rest of the series with the significant increase in confidence levels are 95% and 99%. The second cluster consists of Ahar, Sarab, Mianeh and Julfa stations that mentioned phenomenon of jointly in the time series in March with a significant increase in the same levels of trust. Also the test results from other variables show that despite a series of meteorological variables, no significant trends were, but due to the influence of the reference crop evapotranspiration and the significant impact it has on the superposition. Finally, we should acknowledge that the study of climate change in the region, is not just dependent on the climate variables and could be caused by other variables too.
Research Article
Mohammad Reza Nikpour; Davoud Farsadi
Abstract
Formation of shock waves has an important role in supercritical flows studies. These waves are often occurring during passage of supercritical flow in the non-prismatic channels. In the present study, the effect of length and convergence of contraction wall of open-channel was investigated on hydraulic ...
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Formation of shock waves has an important role in supercritical flows studies. These waves are often occurring during passage of supercritical flow in the non-prismatic channels. In the present study, the effect of length and convergence of contraction wall of open-channel was investigated on hydraulic parameters of shock waves using experimental model. For achieving to this goal, values of depth and instantaneous velocity were measured in various points of shock waves observed in contractions for four Froude Numbers. The results showed that for 63% decreasing the length of contraction, the values of maximum velocity and waves height averagely increased to the amount of 23.6% and 2.77×102%, respectively. Also for the fixed length of contraction, by changing the form of walls from straight-wall to convex-wall the mentioned values averagely decreased to 6.9% and 35.2%, respectively.
Research Article
shamsollah Ayoubi; Mohammad Reza Mosaddeghi
Abstract
Soil surface shear strength is an important parameter for prediction of soil erosion, but its direct measurement is difficult, time-consuming and costly in the watershed scale. This study was done to predict soil surface shear strength using artificial neural networks (ANNs) and multiple linear regression ...
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Soil surface shear strength is an important parameter for prediction of soil erosion, but its direct measurement is difficult, time-consuming and costly in the watershed scale. This study was done to predict soil surface shear strength using artificial neural networks (ANNs) and multiple linear regression (MLR) and to rank the most important soil and environmental attributes affecting the shear strength. A direct shear box was designed and constructed to measure in situ soil surface shear strength. The device can determine two soil shear strength parameters i.e. cohesion (c) and angle of internal friction (φ). The study area (3500 km2) was located in Semirom region, Isfahan province. Soil surface shear strength was determined using the shear box at 100 locations. Soil samples were also collected from 0-5 cm layer of the same 100 locations at which the surface shear strength was measured using the shear box. Particle size distribution, fine clay content, organic matter content (OM), carbonate content, bulk density and gravel content were determined on the collected soil samples. Normalized difference vegetation index (NDVI), the type of land use and geology were also determined. The MLR and ANNs were used to model/predict soil surface shear strength (c and φ). In order to compare the modeling methods, coefficient of determination and root mean square errors were used as efficacy indices. The results showed that ANN models were more feasible in predicting soil shear strength parameters than MLR models due to capability of ANN models in deriving nonlinear and complex relations between the parameters. Results of sensitivity analysis for ANN models indicated that NDVI, bulk density and fine clay content are more effective parameters in predicting c in the studied region. Also it was found that sand content, bulk density and NDVI were more effective parameters and OM/clay ratio and organic matter content were less effective parameters in predicting φ in the region.
Research Article
Adel Reyhanitabar
Abstract
Knowledge about the P critical level and plant response to application of P can effectively help with the proper use of this element. In this study, P critical level for corn (Zea mays L.) was determined in 25 combined soils samples from corn fields of East Azerbaijan province during 2011-2012. Corn ...
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Knowledge about the P critical level and plant response to application of P can effectively help with the proper use of this element. In this study, P critical level for corn (Zea mays L.) was determined in 25 combined soils samples from corn fields of East Azerbaijan province during 2011-2012. Corn have been cultivated in two level of P (zero and 40 mg P kg-1) as a factorial experiment in a randomized complete blokes design with three replications .After 60 days, the plant growth parameters in shoot and root were measured. According to the results, in studied soils, clay content ranged from 12.4 to 57.3 with a mean 31.1 %. Calcium carbonate equivalent ranged from 7 to 35 with a mean 21.5 % and active calcium carbonate ranged from 1.47 to 10.78 with a mean 5.1 %. Application of P significantly increased shoot and root dry weight and their P content. According to the results, applied phosphorus levels, soil type and their interaction had a significant effect on corn growth parameters. Critical level of soil P for corn with Olsen-P, based on 90% relative yield, was determined 12, 14.44 and 10.46 (mg P kg-1 soil) by using graphical Cate–Nelson, Cate–Nelson analysis of variance and Mitscherlich-Bray methods, respectively. Mitscherlich-Bray equation coefficient C1 and C2, for Olsen-P, were 0.0956 and 0.0073 (kg soil mg-1P) respectively. Dry weight of shoot was positively and significant correlated with Olsen –P.
Research Article
Mohamad Ebrahim Khajepour
Abstract
Dynamic stream flow (River Ecosystem) becomes static mound (Lake Ecosystem) after constructing dam on the river. The most important difference between them is of retention time and stratification which induce different qualification to water river prior to reservoir and afterwards. In this study, heat ...
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Dynamic stream flow (River Ecosystem) becomes static mound (Lake Ecosystem) after constructing dam on the river. The most important difference between them is of retention time and stratification which induce different qualification to water river prior to reservoir and afterwards. In this study, heat distribution within15-Khordad Reservoir was simulated using 2-D laterally averaged CE-QUAL-W2 model during the year 1997. Then, results which obtained through this model were made comparison by those of 1-D DYRESM model and field data as well. Results showed that both of models are succeeded in simulation of the reservoir temperature profiles in turn over period, hypolimnion and metalimnion forecasting. But DYRESM model was weak in simulation of epilimnion temperature forecasting in stratification period. In the following, two models were used to calculate the heat flux relationships that are aimed at achieving these differences. Since 15Khordad dam is located in an area which evaporation is an important factor, two different equations to calculate the heat flux model is used to evaporate, lead to underestimation of the actual amount of evaporation in the DYRESM model and the difference in temperature epilimnion simulations compared with measured values.
Research Article
Ali reza Karimi; Isa Esfandiarpour Borujeni
Abstract
Soil maps are the common sources of soil information for land evaluation and land use planning. The objective of this study was to evaluate the capability of conventional and geostatistical methods for mapping selected physical (sand, silt and clay) and chemical (carbonate calcium equivalent and pH) ...
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Soil maps are the common sources of soil information for land evaluation and land use planning. The objective of this study was to evaluate the capability of conventional and geostatistical methods for mapping selected physical (sand, silt and clay) and chemical (carbonate calcium equivalent and pH) soil properties. Based on interpretation of aerial photographs, satellite images and field observations, five geopedologic map units were identified in an area of about 12 km2 in southern Jiroft. 100 surface soil samples (0-20 cm) were taken from a regular grid of 500 × 250 m. The results indicated that geopedological map units were significantly different in at least one soil property. Differences of characteristics between units are resulting differences in geomorphic processes. Continuous soil maps prepared by the ordinary kriging also revealed continuous variations of characteristics in accordance with the changes in geomorphic processes. However, variations between units obviously recognizable in the boundary of units were not revealed by the geostatistical method. Based on results of this study, the conventional method is proposed for large areas (small scale maps) and geostatisticals method for small areas (large scale maps) are proposed for soil mapping.
Research Article
Mohammad Nazeri Tahrudi
Abstract
The application of statistical theory and probability analysis of hydrologic time series is assumed that the variables are normally distributed. Since many time series are not normal, it is required prior to any analysis and modeling, they looked normal. This conversion is done by Const. In this study, ...
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The application of statistical theory and probability analysis of hydrologic time series is assumed that the variables are normally distributed. Since many time series are not normal, it is required prior to any analysis and modeling, they looked normal. This conversion is done by Const. In this study, using 12 common function to convert the normalized data, the average monthly rainfall in different regions of Iran into the data were normally distributed and the skewness coefficient, superior functions in each climate zone was Iran. The results showed that the data used in hot and dry regions with a square, as well as normal and the rest of the climate zones are likely to become a tropical area, Johnson and temperate regions selected for the inverse transform
Research Article
habib beigi
Abstract
Boroujen–Fradonbeh plain is one of the nine main agricultural hubs of Charmahal Provine. The aim of this study was to define and map a deficiency index of soil micronutrients and the effect of wastewater application on it. For this, 200 surface soil (0-30 cm) samples were randomly collected and plant ...
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Boroujen–Fradonbeh plain is one of the nine main agricultural hubs of Charmahal Provine. The aim of this study was to define and map a deficiency index of soil micronutrients and the effect of wastewater application on it. For this, 200 surface soil (0-30 cm) samples were randomly collected and plant available concentrations of copper, zinc, iron, and manganese were determined. After variography and determining the most suitable spatial estimation method, maps of each micronutrient was drawn, normalized, and ranked. An integrated deficiency map was then constructed using the weights from rank maps. According to the maps of copper, zinc and iron, the available concentrations increased from west to east of the plain. This increase was attributed to the wastewater irrigation. The mean value of the integrated map, namely 85.5, indicated the seroius soil deficiency of micronutrients in this plain where 34% of the area was showing severe deficiency. Wastewater application has increased the overall availability of micronutrients by 4%. Sensivity analysis indicated that the map was most sensitive to zinc. Therefore, zinc concentration must be monitored with more precision and frequency across the plain.
Research Article
saleh sanjari; Saeid Barkhori
Abstract
Geomorphologies have an important role in soil genesis and micromorphology. So for survey of pedogenic processes at different levels of geomorphic awareness of soil micromorphology a characteristic is essential. In this study micromorphological properties of soils in the south Roudbar region, part of ...
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Geomorphologies have an important role in soil genesis and micromorphology. So for survey of pedogenic processes at different levels of geomorphic awareness of soil micromorphology a characteristic is essential. In this study micromorphological properties of soils in the south Roudbar region, part of Jazmoryan area study and affected geomorphology on this properties were investigated. In this study, seven soil profiles in playa and alluvial fans landforms that each of them was divided into several different surface geomorphic dug and samples were taken for preparation of thin sections. Geomorphic surfaces of thin sections in median geomorphic and base of alluvial fans represented clay coating, lenticular and interlocked plates of gypsum crystal and gypsum infilling in by and 2Bt1 horizons. While in the levels of different geomorphic surfaces landform playa were shown gypsum infilling and sporadic clay coating and composed pedofeatures included clay coating and calcite. Toward geomorphic surface playa saline puffy ground was added to lenicular crystals and gypsum microcrystals. The view of clay coating in paleosol according to current climate there is evidence of sufficient rainfall and humid paleoclimate for leaching and transport of clay. Also the presence of composed pedofeatures is indicated polygenetic of these soils. Observation of sporadic clay coating is showed natric horizon in effected of sodium ions diffusion were moved and accumulated. Overall, we conclude that presence of micromorphologic observations is showed paleoclimate and wet and dry periods in the last.
Research Article
sarvin ghavidel; sarvin zamanzad ghavidel
Abstract
Forecasts of streamflows are required for many activities associated with the planning and operation of components in a water resource system. This paper demonstrates the application of two different intelligent approaches including adaptive neuro-fuzzy (ANFIS) based on grid partition and Gene Expression ...
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Forecasts of streamflows are required for many activities associated with the planning and operation of components in a water resource system. This paper demonstrates the application of two different intelligent approaches including adaptive neuro-fuzzy (ANFIS) based on grid partition and Gene Expression Programming (GEP) for the prediction of monthly streamflows. In the first part of the study, ANFIS and GEP models were used in one-month ahead streamflow forecasting and the results were evaluated. Monthly run-off data of 21 years from two stations, the Safakhaneh Station on the Sarough-Chay Stream and the Senteh Station on the Kherkherh-Chay Stream in the Zarrineh-rud Basin of Iran were used in the study. The effect of periodicity on the model’s forecasting performance was also investigated. By application of periodicity coefficient in GEP model, determination coefficient in the case of the best input combination for Safakhaneh and Senteh increased 0.19 and 0.25, respectively. In the second part of the study, the performance of the ANFIS and GEP techniques was tested for streamflow estimation using data from the nearby river. The results indicated that the GEP and ANFIS models could be employed successfully in forecasting streamflow. In this case, for the best input combination, root mean square error (RMSE) for ANFIS and GEP obtained equal to 4.88 and 4.89 respectively. However, GEP is superior to ANFIS in giving explicit expressions for the problem.
Research Article
mahdi esmaeli varaki
Abstract
After construction of bridge pier in a river, a 3D complex flow pattern forms around piers and erosion of bed material occurs and if foundation depth or piles depth was not sufficient, the bridge will be collapsed. One of devices to reduction of scour around bridge piers is an installation of sill beside ...
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After construction of bridge pier in a river, a 3D complex flow pattern forms around piers and erosion of bed material occurs and if foundation depth or piles depth was not sufficient, the bridge will be collapsed. One of devices to reduction of scour around bridge piers is an installation of sill beside of piers. In this research, effect of sill on reduction of scour around the inclined bridges piers group under various hydraulic condition and top level of installation of foundation was investigated experimentally. The model of bridge pier was 1/190 scaled of 8th bridges of Ahvaz, Iran, which had inclined rectangular of 2.5 cm length and 3.5 cm width and was placed on the foundation of 10 cm width and 16 cm of length with inclination of 28 degree. Experiments was conducted for different location of sill (front, middle and downstream) of foundation which installed at relative level, height of top of foundation to width of it, -1, -0.5, 0 and 1. Comparison of results showed that installation of sill in front of foundation had the best performance to decrease of scour depth. Furthermore, the reduction of scour depth as the top level of foundation was placed at same level of bed, was considerable.
Research Article
nona sheikholeslami
Abstract
Evapotranspiration is one of the most important parameters that its understanding is necessary for estimating crop water requirement and design of irrigation systems. This phenomenon is greatly influenced by climatic parameters. In this study, the relative importance of variables affecting this phenomenon ...
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Evapotranspiration is one of the most important parameters that its understanding is necessary for estimating crop water requirement and design of irrigation systems. This phenomenon is greatly influenced by climatic parameters. In this study, the relative importance of variables affecting this phenomenon was evaluated and the reference evapotranspiration was estimated using principal component analysis and factor analysis. Daily scaled measurements for the period of 1991-2005 were obtained from synoptic stations located in Mashhad Khorasan Razavi provience, Iran. Mashhad has a semi-arid climate area. The measurements included the relative influence of temperature (T) (maximum, average and minimum), relative humidity (RH), sunshine hours (Rs), and the wind speed at a height of two meters above the ground (U2). The multiple linear regressions were used to estimate evapotranspiration. T-statistic with a significant level of 5% was used for the main components. The evapotranspiration was correlated more with T (minimum. maximum, and average), and relative humidity as than wind speed or sunshine. PC1 had more effect than PC2 (with coefficients of 0.694 and 0.556, respectively). MLR-PCA and MLR with coefficients of 0.903 and 0.897 (respectively) indicated higher ability for PCA method.
Research Article
Abstract
In many areas, the main source of surface and groundwater nitrogen pollution is agriculture and simulation models are useful tools in determining the contribution of nitrogen produced by agriculture in pollution of water resources. In this research, leaching of nitrate on a loam-silty to loam soil was ...
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In many areas, the main source of surface and groundwater nitrogen pollution is agriculture and simulation models are useful tools in determining the contribution of nitrogen produced by agriculture in pollution of water resources. In this research, leaching of nitrate on a loam-silty to loam soil was measured and simulated using LEACHN model after calibration. The experimental design was complete randomize block. The planting media consist of 15 PVC lysimeters (soil column) with 40 cm diameter and 120 cm height. In these lysimeters, maize (Singel Cross 704) was planted. The nitrogen treatments were 0.0 (control), 150, 200, 250 and 300 kg N/ha as urea with three replications. The results were showed that at 120 cm soil depth and the end of growing season, the nitrate leachate in 150, 200, 250, and 300 kg ha-1 treatments were increased 132, 174, 134 and 182% relative to control, respectively. Comparison between the measured and simulated results showed that LEACHN overestimated the leached nitrate in drainage water with the relative error between 11.3% (300 kg ha-1 treatment) and 88.6% (control). The order of accuracy in simulations was obtained in 300, 200,150 and 250 kg ha-1, respectively. In general, the evaluation of LEACHN model showed that the accuracy of this model for simulation of nitrate leachate was relatively good.
Research Article
Ali Golkarian
Abstract
One of the most important objectives in hydrological studies is quantitative rainfall-runoff process estimation at the basin. Several methods and models have been created in order to simulate the Rainfall-Runoff process that each one has its’ own advantages and disadvantages. The aim of this study ...
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One of the most important objectives in hydrological studies is quantitative rainfall-runoff process estimation at the basin. Several methods and models have been created in order to simulate the Rainfall-Runoff process that each one has its’ own advantages and disadvantages. The aim of this study is to investigate the capability of the Geomorphologic Instantaneous Unit Hydrograph model in flood hydrograph development and comparing its’ performance with Snyder, SCS and Triangular models. In order to implement the mentioned methods, Rainfall-runoff data were collected for 14 events and direct hydrograph was obtained. According to the statistical indicators such as RMSE, MRE and Nash-Sutcliff Coefficient, comparison of the observed and estimated hydrographs depicted that the GIUH method was the most efficient in peak discharge estimation, and Triangular, SCS and Snyder models were the next, respectively. Also according to the results, Snyder, GIUH, Triangular and SCS methods have the most efficiency to predict the time to peak, respectively. In addition the results indicate a low estimation for GIUH and SCS methods in peak discharge prediction and over estimation for Snyder and low estimation for GIUH method in time to peak prediction.
Research Article
